Cushioned handle for portable percussive tools



/ March 7., E950 F. J. HORVATH CUSHIONED HANDLE FOR PORTABLE PERCUSSIVE TOOLS Filed DGO. 22, 1945 .II-ll..

F 5. mm

INVENTOR. J. HORVATH FRANK wh.. mo.

ATTORNEYS Patented Mar. 7, 1950 CUSHIONED HANDLE FOR PORTABLE PERCUSSIVE TOOLS Frank J. Horvath, Cleveland, Ohio, assgnor t The Cleveland Pneumatic Tool Company,

Cleveland, Ohio, a corporation of Ohio Application December 22, 1945, Serial No. 636,699

4 Claims.

The present invention relates to impact type tools and, more particularly, to portable pneumatic tools of the reciprocating plunger or hammer type.

Impact type tools vibrate considerably during operation. This is particularly true of pressure uid operated tools of the reciprocating plunger or hammer type. In tools of this character the force of the pressure fluid which reciprocates the plunger acts equally upo-n the ends of the cylinder but in an opposite direction to that in which it acts upon the plunger. This tends to reciprocate the cylinder producing vibrations and shock which are normally transmitted directly to the tool mounting or support,y which in the case of a hand held tool, is the hand or hands of the operator.

One of the principal objects of the invention is the provision of a novel and improved impact tool of the pressure fluid operated type comprising shock absorbing means interposed between the motor or impact producing mechanism and the support or handle of the tool.

Another object of the invention is the provision of a novel and improved impact tool of the pressure fluid operated, reciprocating plunger or hammer type comprising fluid shock absorbing means interposed between the motor or impact producing mechanism and the support or handle of the tool.

Ano-ther object of the invention is the provision of a novel and improved hand held impact tool of the pressure fluid reciprocating plunger or hammer type having fluid shock absorbing means interposed between the motor or impact producing mechanism proper and the handle of the tool.

The invention resides in certain constructions and combinations and arrangements of parts and further objects and advantages thereof will be app-arent to those skilled in the art to which it relates from the following description of the preferred embodiment described with reference to the accompanying drawing forming a part of this specification, in which similar reference characters designate corresponding parts throughout the several views, and in which Fig. 1 is a longitudinal sectional view, with portions in elevation, of a pneumatic tool embodying the invention;

Fig. 2 is an enlarged fragmentary sectional View taken approximately on the line 2--2 of Fig. 1;

Fig. 3 is a fragmentary sectional View taken approximately on the line 3 3 of Fig. 2;

Fig. 4 is a transverse sectional view taken approximately on the line 4 4 of Fig. l;

Fig. 5 is a fragmentary sectional View approximately on the line 5-5 of Fig. 4; and

Fig. 6 is an enlarged, fragmentary sectional view of a portion of Fig. l but showing a modified construction.

The invention is herein illustrated and described as embodied in a chipping hammer of a type manufactured by The Cleveland Pneumatic Tool Company of Cleveland, Ohio, however, it is to be understood that the invention is applicable to various 4types of devices other than the parn ticular tool illustrated. For the most part, the tool shown is well-known in the art and only those parts which are necessary to a complete understanding of the invention are herein shown and described in detail.

Generally speaking, the tool shown comprises a motor or impact producing mechanism Aincluding a cylinder or barrel member l0 having a plunger or hammer Il reciprocably supported in the cylinder chamber I2; a handle assembly B including the handle proper I3; means including an automatic plate valve lli and a throttle valve I5 for controlling the ilow of pressure iuid to the cylinder chamber I2 to reciprocate the plunger Il and means comprising a iluid shock absorber for operatively connecting the handle assembly to the motor assembly impact producing mechanism. In the embodiment shown, the handle assembly B is connected to the cylinder assembly of the motor A.

The cylinder assembly comprises a cup-shaped member 20 threaded onto the rear end of the cylinder member proper l0 and which serves to hold a Valve block 2i and valve block cap 22 against the rear end or face of the cylinder member I0. The front face of the valve block 2l abuts the rear end of the cylinder member i El and the rear face of the valve block cap 22 engages the bottom of the cup-shaped member 2li. The valve block 2l and valve block cap 22 are maintained in proper alignment with each other and with the cylinder member l0 by a plurality of dowel pins, not shown. The automatic plate valve Id is located in a suitable chamber 23 formed in a recess in the face of the valve block 2l adjacent to the valve block cap 22.

The cup-shaped member 20 is provided with a plurality of longitudinally spaced, radial, annular flanges 24, 25 on its exterior; a longitudinally extending, central aperture 26 in its closed end; and a transversely extending aperture 21 in the closed end bisecting the aperture 26 and a circular chamber 28 in the bottom of the member. rl'he outer ends of the transversely extending aperture 2'! are closed by plugs 3d, 3i welded or otherwise lxedly secured to the member 25. The member 2D is threadedly connected to the rear end of the cylinder member ES and the two parts are locked together a locking ring 32 located adjacent to the front end of the member 2d and slidably keyed or splined 'to the cylinder member Il). 'I he locking ring 32 has internal splines in mesh with external splines on the cylinder member iii, and a plurality of teeth or jaws on the rear face thereof which engage similar teeth or jaws on the forward face of the member A spring located underneath a. il .id deflector ringr 34 slidably supported on the exterior of the cylinder member le? provides means for normally maintaining the teeth or splines on the rear face of the lock ring 32 in engagement with the teeth on the forward face of the me ber 2l?, thus normally locking the member 2Q to the cylinder member it and preventing relative rotation therebetween. The forward end of the s S2 is fixed to the cylinder member lil while the r ond engages the inwardly eitending ilange at the rear end of the deflector ring which flange in turn engages the forward face of the locking ring 32.

The throttle Tv'alve i5 is sliflably supported in a tubular member ixed u 'n an aperture in the handle member i3. e valve i5 is adapted to be moved against a compression spring 3l interposed between the lower side of the valve I5 and a plug 3S closing the lower end of the member 35 by a plunger t@ also` slidably supported in the handle proper i3. rEhe plunger ll is adapted to be depressed to open the throttle valve l5 by o. throttle lever di pivotally supported in a recess or aperture fsf?. the handle i3. The handle I3 is provided with. a suitable connection d3 for attaching the tool to a source of pressure fluid. The connection is threaded into an aperture 4f! in the handle i3, which aperture is in continuous communication with an annular chamber [l5 a conduit lo in the handle. The chamber 45 surrounds the member intermediate its ends and is in communication with the outer ends oa plurality of apertures El? extending through the wall of the member belov.7 the seat for the throttle valve I5.

Upon being depressed, the throttle lever lli opens the throttle valve l to admit pressure fluid from the annular chamber l5 to the aperture 3S by way of he apertures il? the interior bore 4810i the member 35. From the chamber 35 the fluid pressure is directed by a passage 59 to the transversely extending aperture 2'? and the chamber 23 in the cup-shaped member 2D, The passage in the handle member i3 terminates in a central boss 5i projecting into the bottom of a cylindrical aperture 5?: in the member i3 formed by an annular casing concentric with the cylinder member and into which aperture the rear end of the motor assembly A projects. As will be hereinafter apparent, the motor assembly reciprocates with respect to the handle assembly during operation of the tool and the aperture 2% in the closed end of the member 23 has a recess therein for the reception of a packing ring 5d for preventing the escape of pressure uld through the aperture 2G and around the boss 5l. From the aperture 27 pressure fluid is directed by an annular chamber 55 about the periphery of the valve block 2i and the valve block cap 22 and a radial passage 53 in the valve block 2i, the outer end of which communicates with said All) chamber 5E, to an annular groove 5l in the valve block 2i at the forward side of the automatic plate valve l. Pressure fluid is also directed from the aperture .Z'I, by a passage 58 in the valve block cap 22, to an annular groove 6U at the rear side of the automatic plate valve Ill.

With the parts in the position shown in Fig. l, the plunger o-r hammer II has just completed its forward or power stroke. The automatic valve is in its forward position and pressure fluid is being admitted to that part of the chamber 23 to the rear of the Valve Ill through the passage 53, etc. From the chamber 23 it is directed to the forward end of the cylinder chamber I2 to cause the plunger i! to execute its return stroke by communicating passages ill, S2, 63 in the Valve block cap?, the valve block 2i and the cylinder member it, respectively. The passage G3 extends longitudinally of the cylinder member III and opens into the forward end of the cylinder chamber l2 pressure uid directed thereby to tlie forward end of the chamber I2 will drive the plunger or hammer I'i toward the rear end of the chamber. The rate of flow of pressure fluid from the passage to the passage 6I and in turn to the forward end of the chamber I2 is metered determined by the space between the valve id and the end of the annular flange formed by the annular groove and the longitudinal part of the passage Si at the center of the valve block cap.

As the plunger il moves toward the rear end of the cylinder chamber I2, it closes an exhaust port t5, which had previously been opened by the for vard movement of the plunger, to permit the exhausting of the pressure fluid behind the plunger Il during the power stroke. Continued 'movement of the plunger II toward the rear opens an exhaust port El located forwardly of the exhaust port rlhe exhaust ports 66 and 6l are in communication with a longitudinally extending passage G in the cylinder member I0, which passage is in turn open to atmosphere through a plurality of radial apertures i in the cylinder member its located underneath the deector ring From underneath the deector ring 3d, the pressure fluid escapes through apertures il in the forward wall or flange of the deflector ring. Continued movement of the plunger il toward the rear after the port G6 has been closed causes the pressure of the fluid trapped in the rear part of the chamber I2 to increase until the pressure on the Valve block or forward side of the valve ld is sufficient to shift the Valve iii to the opposite side or end of the chamber 23.' Attention is called to the fact that upon the opening of the exhaust port Si the pressure on the rear or-valve block cap side of the valve Iii drcppedbelow line pressure.

Upon the shifting of the valve M to the rear part of the chamber 2S, the flow of pressure uid to the forward end of the cylinder chamber I2 is discontinued and pressure uid admitted to the rear end of the cylinder chamber l2' from the annular chamber El by a central, longitudinally extending aperture l2 in the valve block 2I through a metering arrangement similar to that previously existing at the rear side of the valve It, and comprising the flange formed by the annular groove 5l and the aperture l2. Pressure fluid admitted' to the rear end or the chamber l2 will drive the plunger or hammer II toward the forward end of the chamber I2 and into engagement with the rear face of the shankIS oil a tool proper C which, in the present instance,

is' a chipping tool or steel. Prior to impacting the tool C, the plunger will open the exhaust port 66 permitting the pressure fluid in the rear end of the cylinder chamber I2 to escape to atmosphere, however, the hammer continues its forward movement until it strikes the tool. When the pressure in the rear part of the cylinder chamber I2 has decreased to such an extent that the pressure against the valve block side of the valve I4 is less than the pressure on the opposite side thereof, the valve will .be automatically thrown to the position shown in Fig. 1 and the cycle of operation repeated. Tools of the character referred to usually have operating cycles of from 2000 to 3000 strokes per minute.

The rear end of the cylinder or motor assembly is resiliently held in the aperture 52 by a resilient, annular member 80 interposed between the rear face of the cup-shaped member 20 and the bottom of the aperture 52, and a resilient, annular member 8| interposed between the front face of the flange 21| on the member Zl and the rear face of a flange 82 on a nut-like member 83 threaded onto the forward end of the flange 53. In the embodiment shown, the members 80, 8| are composed of soft rubber or rubber-like material, however, any suitable resilient member or material may be employed. Any suitable means may be employed for locking the nut 83 onto the casing 53. As shown this is accomplished by one or more small setscrews 84 located at the joint between the nut and handle member i3. The resilient members 8|), 8| permit limited movement of the cylinder assembly within the handle assembly longitudinaly of the cylinder chamber l2.

Relative rotation between the cylinder assembly and the handle assembly is prevented .by a plurality of locking segments 85, see Figs. 2 and 3, located in an annular chamber 86 between the rear end of the member 20 and the rearward periphery of the casing 53 of the handle member I3. The segments 85 are Xed relative to the member 20 by being held in engagement with the rear face of the annular flange 25 by the resilient member 80. The members S5 are provided with internal splines 8l extending the entire length thereof and which engage suitable splines in the rear end of the member 20 and with relatively short, external splines 88 which engage within elongated, internal splines 0o in the handle member I3.

In order to assist the resilient members 80, 8| in absorbing the shock and vibrations produced by the motor or impacting mechanism and preventing their transmission to the handle proper, the handle assembly includes piston-like means in the form of an annular ring 0|, hereinafter referred to as an absorber ring, located in the space intermediate the radial, annular anges 24, 25 on the member 25 and fixed with respect to the handle I3 and the casing 53 against movement lengthwise of the tool by a plurality of radially spaced members 92 having grooves in their lower ends adapted to receive the ring 9|. Each of the members 92 is provided with a shank 93 which projects into a suitable aperture in a hollow setscrew 94 threaded into tapped apertures in the casing 53. The setscrews 04 may be locked in any suitable manner. As shown they are drilled through their heads and have a safety wire 95 inserted therethrough. The absorber ring 3| must be of the split type to permit its installation over one of the anges 24, 25 and, as shown, it is of the step-cut type and has its ends pinned together, after installation, by a pin 5 96. Alternatively any suitable type of split ring may be employed, such as, one having a diagonal scarf joint.

In the embodiment illustrated in Figs. 1 to 5, the chamber |00 formed by the annular flanges 24, 25 and the internal wall of the casing 53 of the handle member I3 and within which chamber the absorber ring 9| is located, is in continuous communication with the chamber 55 around the exterior of the valve block 2| and valve block cap 22 by passages lill, |02. The passage IUI opens into the forward end of the chamber |00 and the passage |02 opens into the rear end of the chamber. The passage lill communicates with the passage |02, which latter passage extends to the chamber 55.

Packing rings |03, |04 located in suitable grooves in the annular flanges 24, 25 prevent the escape of pressure fluid from the chamber |05, however, suitable apertures, not shown, are provided in the casing 53 in front of the flange 24 and to the rear of the iiange 25 to permit the escape to atmosphere of any pressure fluid which leaks past the packing rings E03, |04. In a similar manner a port or passage |05 in the handle member I3 permits any pressure fluid which might leak by the packing ring 54 to escape from the bottom of the aperture 52.

The motor and handle assemblies are normally held by the resilient members 30, 8| in the position shown in Fig. i, the former of which resilient members is considerably thicker so as to permit relatively greater movement of the cylinder assembly toward the rear of the tool since the rearward impetus of the cylinder assembly is greater than its forward impetus. Similar provision has also been made in the sliding joint :between the projecting boss 5| and the member 20 and the length of the splines B'I at opposite sides of the external splines 88 on the member 85. For the same reason, the ring 9| is located slightly to the rear of the center of the chamber |00. The ring 9| is provided with a plurality of spaced, restricted apertures |06 extending therethrough and the pressure fluid in the chamber |50 cooperates with the ring 9| to assist in absorbing the shock produced by the reciprocation of the plunger or hammer il and to damp out the vibrations produced before they are transmitted to the handle proper. Opposite sides of the piston-like member or ring 5I have equal areas exposed to the action of the pressure fluid in the cylinder or chamber |00 and the construction and operation thereof are that of a double, equal acting fluid shock absorber.

An alternative construction is shown in Fig. 6. The tool shown therein is similar to that shown in Figs. l to 5 and described above, with the exception of the fact that the passages lill, 502 are omitted and the chamber i 0'.' corresponding with the chamber |00 of the preferred embodiment lled with a light oil. rllhe other parts of the device are duplicates of those shown in the preferred embodiment and are designated by the same reference characters.

It is believed that the operation of the device will be apparent from the foregoing description. Sui-lice it to say that the shock and vibrations produced by the plunger or hammer I| are absorbed by a combined action of the resilient members 85, 8l and the double, equal acting fluid shock absorbing mechanism comprising the ring 9|, etc. The restricted conduit means connecting the portions of the chamber at opposite sides of the piston-like ring 9| allow a certain amount of fluidito ow'from thexchamber at one side of the ring to; thel other. The holes 59S through the piston-like ring 9i may be eliminated in the embodiment shown in Figs. 1 to 5 because opposite endsof the chamber 99 are connected by the conduits lili, 292 but in the embodiment shown in Fig. 6, the holes are essential and serve asa means for metering the iiow of liquid from one part to the other ol the chamber. As an al-` ternative construction', the holes lcould-be replaced by a conduit in the cylinder assembly connecting opposite ends of the chamber E971.

From the foregoing description o the preferred embodiments, it will be apparent that the objects heretoore enumerated and others have been accomplished and that there has been provided a novel and improved tool of the impact type having improved means between the tool proper and the handle or support thereof for absorbing the shock produced during operati-on. While the preferred embodiments have been described in considerable detail, the invention is not limited to the particular construction shown and i., is my intention to hereby cover all adaptations, modifications and uses thereof which come within the practice or those skilled in the art to which the invention relates and within the scope of the appended claims.

Having thus described my invention, I claim:

1. In a pressure fluid operated tool of the character referred to, the combination of a motor assembly, a supporting assembly for said motor assembly including a handle member formed with a casing tted over one end portion of said motor assembly, means for operatively connecting said assemblies for relative longitudinal movement therebetween including a slidingr joint between said motor assembly and casing, and double acting fluid shock absorbing means including a fluid containing annular chamber intermediate the ends oi said sliding nt, and a piston-like member carried by said casing extending radially and inwardly therefrom into said chamber whereby shocks or vibrations produced by said motor assembly are absorbed before reaching said supporting assembly.

2. In a pressure uid operated tool of the character referred to, the combination or" a cylinder assembly, a handle assembly for said cylinder assembly, means for operatively connecting said assemblies for relative longitudinal movement therebetween, and shock absorbing means between "d assemblies including longitudinally spacedl e.. rnal annular flanges on said cylinder assembly, iluidtight sliding joint between said` 3. In a pressure iluid operated tool of the character referred to, the combination of a substantially cylindrical motor assembly, a supportinof assembly for said motor assembly includa handle member tted over one end portion ci said motor assembly, means for operatively connecting said assemblies for relative longitudinal movement therebetween, and means for retarding said relative movement including a fluid chamber between said motor assembly and handle, a piston-like element carried by said handle member extending radially and inwardly therefrom into said chamber, a fluidtight joint be .veen said motor assembly and handle member adjacent each end of said chamber, and a restricted rluid conduit connecting the portions of said chamber at opposite sides of said piston-like member.

4. In a pressure fluid operated tool of the character rel erred to, the combination of a cylinder assembly including a cup shaped member forming one end portion of said assembly, a supporting assembly for said cylinder assembly including handle member fitted over said cup shaped member, means for operatively connecting sai-d assemblies for relative longitudinal movement there-bet" een including a sliding joint between said members, and means for retarding said relative movement including a fluid cha nber atermediate the ends of said sliding joint forme by a groove on the external wall of said cup shaped member covered by the inner wall of said handle member, a piston-like element carried by said handle member extending therefrom into said chamber, and a rW .cted conduit connecting the portions of said chamber at opposite sides of said pistonlilae member.

FRANK J. HORVATH.

REFERENCES The following references of record in the nie o this patent:

UNITED STATES PATENTS 

